#!/usr/bin/env python3
import sys

if sys.argv[1:]:
    s = sys.argv[1]
else:
    print('Usage: {0} <string>'.format(__file__))
    exit()

# 统计
d = {}
for i in s:
    if i in d:
        d[i]+=1
    else:
        d[i]=1

# 输出
print('{0} : {1}'.format('字母', '次数'))
for i in sorted(d):
    print('{0} : {1}'.format(i, d[i]))
